Insertion device and method

ABSTRACT

The present invention provides an insertion device and method for implanting a biosensor into a patient subject. In one embodiment, a biosensor is stored in the instrument&#39;s hydration chamber which enables the biosensor to maintain proper hydration and sterilization prior to insertion. The instrument further includes a plunger that travels along a channel within the support device. After the biosensor is placed into the channel, the user pushes the plunger causing the biosensor to move through the channel and a hollow tube and into the patient subject. The present invention also provides for packaging and storing a biosensor and insertion device so that the biosensor is hydrated and sterile prior to insertion.

RELATED APPLICATIONS

This application is a continuation of and claims priority to pendingU.S. patent application Ser. No. 11/447,980, filed on Jun. 7, 2006,which claims the benefit of provisional application No. 60/688,371,filed Jun. 8, 2005, each of which are incorporated herein by referencein their entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to the insertion of subcutaneousbiosensors and, more specifically, to a device and method for implantinga biosensor at a selected site within the body of a patient.

2. Discussion of Related Art

Biosensors have been increasingly used to monitor physicalcharacteristics of human and animal subjects. Such biosensors can beplaced underneath the skin of a subject and used to measure, forexample, blood glucose levels. An example of such a biosensor can befound in U.S. Pat. No. 6,330,464, the disclosure of which isincorporated herein by reference. There, an optical-based biosensor isdisclosed which is capable of detecting the presence or amount ofanalyte in blood. Of course, such biosensors must be compatible withhuman and animal tissue and must maintain their integrity withinmoisture-rich environments. Oftentimes, the exterior of the biosensorsare made of materials sensitive to the drying effects of air and must beconstantly hydrated in order to maintain device integrity. For example,U.S. Pat. No. 6,330,464 discloses optical based sensors with fluorescentindicator molecules distributed throughout a matrix layer coated on theexterior surface of the sensor body. Of course, the biosensors must alsobe kept sterilized prior to insertion into the subject in order to avoidinfection.

Certain insertion devices are known in the art for implanting sensorssubcutaneously into subjects. For example, U.S. Pat. No. 4,787,384discloses a system and device for implanting a solid identificationmarker underneath the animal's skin that allows scientists to mark agiven animal for tracking or testing purposes. However, this system hasseveral disadvantages. First, the system contains at least oneprojection extending into the hollow tube that is configured to trap themarker in place by friction fitting. Such a projection could damage thecoating of a biosensor, especially in the case where the exteriorsurface of the biosensor is coated with an indicator chemistry and thelike. Also, the disclosure of U.S. Pat. No. 4,787,384 does not teach orsuggest providing for consistent hydration of the marker for the periodprior to insertion. Accordingly, the disclosure provides no means ofhydrating a biosensor.

Insertion devices for implanting sensors are also described in, amongothers, U.S. Pat. Nos. 6,936,006, 5,074,318 and 5,002,548.

What is desired, therefore, is a system and method to overcome at leastsome of the disadvantages of the prior art and to effectively store andinsert sterilized biosensors into subjects while preserving biosensorintegrity.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides an insertion device havinga support device including a channel that houses a slidable plunger. Theplunger has an extension arm that is attached to the plunger and extendsoutside of the support device through a slot allowing the user to slidethe plunger back and forth within the channel. In one embodiment, theuser can monitor the position of the plunger by viewing the location ofthe extension arm relative to a plurality of ramps located on thesupport device.

The insertion device in accordance with one aspect of the presentinvention also provides a hydration storage compartment for the storageof the biosensor preferably in a sterile, hydrating environment. In oneembodiment, the hydrating compartment includes a plug that resides abovethe biosensor which enables the biosensor to be securely maintainedwithin the hydrating compartment. In another embodiment, the biosensoris sandwiched between the plug and plunger as it resides in thehydration storage compartment. In a preferred embodiment, the plugcontains a slot that allows fluid to enter and exit the hydrationstorage compartment so that the biosensor is properly hydrated duringstorage and prior to insertion into the patient.

The insertion device according to one aspect of the invention alsoincludes a hollow tube having dimensions that allow the plunger andbiosensor to travel within the hollow tube. In one embodiment, a distalend of the hollow tube is configured such that it can be inserted intothe skin of the subject. Also in accordance with this embodiment, theplunger, biosensor and hollow tube are configured such that thebiosensor can be driven out of the distal end of the hollow tube by theplunger and into the desired location in the subject.

In another aspect, the present invention provides at least one methodfor inserting the biosensor into the subject. In the preferred method,the user places his/her thumb, for example, on the extension arm andmoves the extension arm in proximity to the first ramp, which allows thebiosensor to be located in the channel of the hollow tube. The user thenpushes the plug down toward the channel to secure the biosensor into thechannel. The user then pushes the plunger toward the distal end of theapparatus by using the extension arm to a position in proximity to thesecond ramp. The user then continues to push the plunger over the thirdramp indicating to the user that the biosensor has exited the distal endof the hollow tube and has entered the subject.

In another aspect, the present invention provides a package assembly forstoring the insertion device so that the insertion device and biosensorremain sterile and properly hydrated prior to use. In a preferredembodiment, the package assembly containing the insertion device issealed with a sterile barrier allowing the insertion device andbiosensor to be sterilized. In another embodiment, the sterile barriercontains a septum through which hydrating fluid is permitted to enterthe sealed, sterilized package assembly, thereby allowing the insertiondevice and biosensor to be hydrated. In an additional embodiment, thepackage includes flaps and slotted clasps extending from the back of thepackage which enables the package to stand vertically. The verticalorientation of the package advantageously allows the sterile hydratingfluid to penetrate the hydration chamber and bathe the biosensor priorto use without leaking from the package cavity.

The above and other features and advantages of the present invention, aswell as the structure and operation of preferred embodiments of thepresent invention, are described in detail below with reference to theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated herein and form partof the specification, help illustrate various embodiments of the presentinvention and, together with the description, further serve to explainthe principles of the invention and to enable a person skilled in thepertinent art to make and use the invention. In the drawings, likereference numbers indicate identical or functionally similar elements.

FIG. 1 a shows an exploded view of the insertion device in accordancewith one aspect of the present invention.

FIG. 1 b shows a top view of the insertion device of FIG. 1 a.

FIG. 1 c. shows a side cutaway view of the insertion device of FIG. 1 a.

FIG. 2 shows the insertion device of FIG. 1 and illustrates thebiosensor in the hydration storage compartment in accordance with oneaspect of the present invention.

FIG. 3 shows the insertion device of FIG. 1 and illustrates plungerextension positioned such that the biosensor is permitted to move intothe channel in accordance with one aspect of the present invention.

FIG. 4 shows the insertion device of FIG. 1 and illustrates thepositioning of the biosensor in the channel in accordance with oneaspect of the present invention.

FIG. 5 shows the insertion device of FIG. 1 and illustrates thepositioning of the biosensor toward the distal end of the hollow tube inaccordance with one aspect of the present invention.

FIG. 6 shows the insertion device of FIG. 1 and illustrates thebiosensor being ejected from the end of the hollow tube in accordancewith one aspect of the present invention.

FIG. 7 a illustrates a front view of a sterile package assembly forstoring an insertion device in accordance with another aspect of thepresent invention.

FIG. 7 b illustrates a front view of a sterile package assembly forstoring an insertion device with a sterile barrier layer and septum inaccordance with another aspect of the present invention.

FIG. 7 c illustrates a side view of the sterile package assembly forstoring an insertion device in accordance with another aspect of thepresent invention.

FIG. 7 d illustrates a rear view of the sterile package assembly forstoring an insertion device in accordance with another aspect of thepresent invention.

FIG. 7 e illustrates a clasp assembly of the sterile package assemblyfor storing an insertion device in accordance with another aspect of thepresent invention.

FIG. 8 shows a side cutaway view of an insertion device in accordancewith another embodiment of the present invention.

FIGS. 9 a and 9 b show the hydration chamber of the insertion devicehaving a breakable floor in accordance with another embodiment of thepresent invention.

FIGS. 10 a and 10 b show the channel of the insertion device havingfirst and second breakable barriers in accordance with anotherembodiment of the present invention.

FIG. 11 shows the plug of the insertion device as being hollow andhaving a breakable bottom in accordance with another embodiment of thepresent invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention includes an apparatus and method for implanting abiosensor (such as, for example, a biosensor for measuring the presenceor amount of blood glucose levels or other analytes of interest) in apatient subject. The present invention also includes an apparatus forpackaging and storing the instrument and biosensor so as to ensurehydration and sterility prior to use.

Referring to FIGS. 1 a, 1 b and 1 c, in one embodiment of the presentinvention, the apparatus 100 includes a hollow tube 102 having anentrance and exit opening. The hollow tube 102 is supported by a supportdevice 104. In a preferred embodiment, the support device 104 contains abiosensor hydration storage compartment 110 which is configured to storethe biosensor 118 and hydrating solution.

A plunger or core 108 is located within the support device 104 and isconfigured to slide within a channel 106 in the support device 104. Thechannel 106 is preferably a circular channel but also may be configuredto have different shapes, such as, for example, square, rectangle ortriangle. The plunger 108 is also configured to slide within the hollowtube 102. The channel 106 is preferably concentric with the hollow tube102. The plunger 108 in one embodiment has a forward and backwardposition relative to the support device 104. The plunger 108 may includean extension or arm 108 a which allows a user of the apparatus 100 tomove the plunger 108 forward and backward in the apparatus 100 along thelongitudinal axis of the channel 106 and hollow tube 102. A slot 116 orthe like may be provided in the support device 104 for allowing theextension 108 a to move freely along the support device 104.

In one embodiment, the present invention may include one or moreelements that facilitate limiting the motion of the plunger 108 andidentifying the location of the plunger 108 along the channel 106 andhollow tube 102. As shown in FIGS. 1 a, 1 b and 1 c, the presentinvention may include any or all of ramps 112 a, 112 b and 112 cprovided on the support device 104. The ramps 112 a, 112 b and 112 c areconfigured to contact the extension arm 108 a in order to limit themotion of the plunger 108 and indicate to the user the location of thebiosensor 118 within the channel 106 and hollow tube 102. For example,in one embodiment, ramp 112 c indicates the backward most location ofthe plunger 108 and, in a preferred embodiment, acts as a stop toprevent further backward movement of the plunger 108, as reflected inFIGS. 3 and 4. Ramp 112 b also may be used, in accordance with oneembodiment, to indicate that the biosensor is located at the distal endof the hollow tube 102, as illustrated in FIG. 5. Ramp 112 a also may beused, in accordance with one embodiment, to indicate that the biosensorhas been ejected from the end of the hollow tube 102 and into thepatient subject, as illustrated in FIG. 6.

In accordance with a preferred embodiment, the support device 104 mayinclude a biosensor hydration storage compartment 110 with hydrationstorage compartment plug 113 which is configured to be inserted into thestorage compartment 110 and positioned adjacent to the channel 106. Thehydration storage compartment plug 113 may have one or more slotopenings 113 a allowing hydration fluid to enter the hydration storagecompartment 110. The plug 113 secures the biosensor 118 within theapparatus 100 hydration storage compartment 110 while the biosensor 118is bathed in hydration fluid. In accordance with another aspect of thepresent invention, the hydration chamber may also receive one or moresterilization fluids, such as, for example, Cidex sterilization fluid.

In accordance with a preferred embodiment, the biosensor 118 is capableof being exposed to sterilizing gas, such as ethylene oxide (ETO) gas,while present within the apparatus 100 and hydration storage compartment110.

The support device 104 of the present invention may be constructed ofany suitable material such as, for example, an injected molded plastic.The hollow tube 102 may be constructed of a suitable, substantiallyrigid material such that the hollow tube may be inserted into the skinof the patient subject. In one embodiment, the hollow tube 102 is aneedle or the like. In another aspect of the present invention, thehollow tube 102 has a distal end which may be beveled or tapered tofacilitate insertion into the patent subject. The support device 104also may have multiple ridges 114 positioned on the bottom surface forergonomic feel during use.

The plunger 108 can be a guide-wire, plastic injected molded piece,stylet, or the like and preferably includes a beveled or tapered distalend 108 b (See FIGS. 1 a, 1 b and 1 c). In one embodiment, the beveledor tapered distal end of the plunger matches the beveled or tapereddistal end of the hollow tube 102. This configuration may help toprevent unwanted coring of body tissue during the insertion process.

FIG. 2 illustrates the insertion device according to one embodiment ofthe present invention where the biosensor 118 is securely positionedwithin the hydration compartment 110 by plug 113. When the extension 108a is positioned in proximity to the third ramp 112 a, the plunger 108will serve as a “floor” for the biosensor hydration storage compartment110, trapping the biosensor 118 in this location when the plug 113 issecured above the biosensor 118.

FIG. 3 illustrates the insertion device according to one embodiment ofthe present invention wherein the plunger extension 108 a is positionedin the backward most position in proximity to first ramp 112 c. Theplunger may be moved to this position by the user by sliding extension108 a in proximity to the first ramp 112 c. At this backward mostposition, the distal end of the plunger 108 moves beyond the location ofthe hydration storage compartment 110. In this position, the biosensor118 no longer has the plunger 108 as a “floor” and, as a result, movesinto the channel 106 in front of the distal end of plunger 108, asillustrated in FIG. 4. In one embodiment, also illustrated in FIG. 4,the hydration storage compartment plug 113 is then pushed downward,ensuring that the biosensor 118 is firmly positioned within the circularchannel 106 and ready for travel along the circular channel 106 andhollow tube 102 and into the subject.

Referring to FIG. 5, the extension 108 a is illustrated in an advancedposition toward the second ramp 112 b. In this position, the distal endof plunger/core 108 contacts the biosensor 118 and pushes the biosensor118 through the circular channel 106 and into the hollow tube 102. Whenthe extension 108 a reaches the second ramp 112 b, this alerts the userthat the biosensor 118 is at the end of the hollow tube 102. At thatpoint, the distal end of the plunger 108 is at its pre-insertionposition 102 a within the hollow tube 102.

FIG. 6 illustrates the insertion device according to one embodiment ofthe present invention wherein the plunger extension 108 a positioned inthe forward most position in proximity to the third ramp 112 a. As theextension 108 a is moved by the user from the second ramp 112 b to thethird ramp 112 a, the plunger 108 continues its movement toward thedistal end of the hollow tube 102 thereby causing the biosensor 118 tobe ejected into the patient subject.

In one embodiment, as the plunger 108 moves toward the distal end of thehollow tube 102, the support device 104 will move in the oppositedirection. This is accomplished, for example, when the thumb (resting onthe extension 108 a) and the forefinger (resting on the ridges 114) movein opposite directions. The plunger extension 108 a will come in contactwith the end of the slot 116 in the support device 104 that will act asa stop when moving the biosensor 118 toward the distal end of the hollowtube 102, signifying ejection of the biosensor 118. In accordance withanother aspect of the present invention, the plunger 108 may berestricted from moving in the backward direction thereby ensuring thebiosensor 118 is fully ejected from the apparatus 100. The tip of thehollow tube 102 is preferably then removed from the subject.

Referring back to FIG. 1 a, in accordance with one embodiment, thebiosensor 118 may be loaded into the hydration storage compartment 110of the apparatus 100 with the extension 108 a positioned in proximity tothe third ramp 112 a. When the biosensor 118 is loaded into theapparatus 100, the hydration storage compartment plug 113 traps thebiosensor 118 in the hydration storage compartment 110. The plug 113remains secured within the walls of the hydration storage compartment110, in one embodiment, by virtue of friction fitting or otherequivalent methods known in the art. In accordance with anotherembodiment of the present invention, the biosensor may be loaded intothe hydration storage compartment 110 when the plunger extension 108 ais in the back position in proximity to first ramp 112 c. In thisembodiment, the plug 113 is fully inserted into the hydration chamber110 thereby securing the biosensor within the channel 106.

As described above, the ramps 112 a, 112 b and 112 c may be provided onthe surface of the support device 104 to limit the movement of theextension 108 a and plunger 108 and to signal to the user the locationof the plunger 108 within the channel 106. For example, the third ramp112 a may be provided toward the distal end of the support device 104 totemporarily lock the plunger/core 108 in place during loading, assembly,shipment and storage of the apparatus 100.

In the preferred embodiment, referring to FIG. 3, the first ramp 112 c,may be a ribbon protruding from the surface of the support device 104,preventing the extension 108 a from moving beyond the backward mostposition. For example, in one embodiment, the first ramp 112 c may be aribbon of material fixed into and extending from the support device 104at the backward most position of the extension 108 a and arching backtoward the rear of the support device 104, as shown in FIG. 3. The firstramp 112 c thereby becomes an obstacle to movement for the extension 108a and plunger 108, and also indicates to the user the location of theplunger 108 and biosensor 118. The first ramp 112 c need not be aribbon, but may be configured as any of a number of protrusionsextending from the support device 104 preventing the extension 108 afrom moving beyond its backward most position. The protrusions can bemade of any material known in the art, including, for example, plasticand/or metal. The first ramp 112 c may also be a part of the supportdevice 104, whereas a plastic mold of the support device 104 couldinclude such a protrusion.

In one embodiment of the invention, as illustrated in FIGS. 5 and 6, thesecond and third ramps 112 b and 112 a can be created using a ribbon ofmaterial extending from the support device 104 in proximity to thedistal end of the support device 104. The ribbon creating the second andthird ramps 112 b and 112 a, in one embodiment, is configured in such away so as to allow the extension 108 a to come to a stop at the secondramp 112 b, but to allow the extension to ride up the second ramp 112 b,over the ribbon body, and down the third ramp 112 a, temporarilysecuring the extension 108 a and plunger 108 in a set position after thebiosensor 118 has been expelled. The ribbon can be configured in such away so as to allow the user to move the extension 108 a back up thethird ramp 112 a, over the ribbon body, and down the second ramp 112 b.The second and third ramps 112 b and 112 a need not be created by aribbon, but may be any of a number of protrusions extending from thesupport device 104. The protrusions can be made of any material known inthe art, including plastic and/or metal. The protrusions forming secondand third ramps 112 b and 112 a may made as integral parts of thesupport device 104 or may be affixed to the support device 104 by knownmeans, such as an adhesive.

In other embodiments, the ramps 112 a, 112 b and 112 c need not beprotrusions, but may be notches or the like in the support device 104,which are configured to engage the extension 108 a at set positions andindicate to the user the location of the plunger 108 and biosensor 118.

The hydration storage compartment 110 is preferably sized to house onlyone biosensor, but the invention is not meant to be limited to such anembodiment. In alternative embodiments (not shown), the hydrationstorage compartment 110 may be constructed to hold multiple biosensors.In still other embodiments, the support device 104 may be configured tohave multiple hydration storage compartments 110 along the surface ofsupport device 104.

The hydration storage compartment 110 can be fabricated from a porousmaterial or include holes to allow liquid to pass into the chamber fromthe outside, such as through slot 113 a in plug 113. In one embodiment,it is intended that the biosensor 118 be placed within the hydrationstorage compartment 110 of the apparatus 100 prior to packaging, asillustrated in FIG. 2. In this embodiment, it is desired that thebiosensor 118 be treated, hydrated, sterilized or the like, after thebiosensor 118 is inserted into the hydration storage compartment 110.Therefore, any number of hydration methods known in the art can be usedto ensure that fluid enters the hydration storage compartment 110.

In another embodiment of the present invention, referring to FIGS. 9 aand 9 b, the hydration storage compartment 110 contains hydrating fluidand a breakable floor 120. In this embodiment, the breakable floor 120prevents the biosensor 118 and fluid from entering the channel 106 priorto use of the device. In this embodiment, the hydration storagecompartment 110 is defined by the walls of the device 115, the breakablefloor 120, and the plug 113. The plug 113, in one embodiment, isnon-porous and creates a fluid-tight seal within the compartment 110,thereby preventing the fluid from leaking outside the compartment 110.In this embodiment, the user moves the plunger extension 108 a back tothe first ramp 112 c and applies pressure to the plug 113 so that thebiosensor 118 breaks through the breakable floor 120 and enters thechannel 106 along with the hydrating fluid. The breakable floor 120 canbe made of any number of materials known in the art that can hold fluidand break open upon suitable pressure without fragmenting, such asaluminum foil, rubber and/or plastic.

In another embodiment of the present invention, referring to FIGS. 10 aand 10 b, the biosensor 118 and fluid are placed within a hydrationchamber 126 which is defined by the channel 106 at a bottom end, sidewalls including a first breakable barrier 122 and a second breakablebarrier 124 located within the channel 106, and the plug 113 at the top.The plug 113 secures the biosensor and seals the fluid within thechannel 106 prior to insertion. In this embodiment, the plungerextension 108 a begins at the position located at the first ramp 112 cand, when moved forward, the distal end of the plunger 108 pierces thefirst breakable barrier 122, and forces the biosensor 118 to breakthrough the second breakable barrier 124 as the biosensor 118 travelsdown the hollow tube 102 and into the subject. This occurs while theplunger extension 108 a moves past the second ramp 112 b to the thirdramp 112 a. In this embodiment, the biosensor 118 and fluid can beloaded into the channel 106, with the plug 113 acting as the roof ofthis hydration chamber 126, securing the biosensor 118 and preventingthe fluid from escaping the chamber 126 prior to use. The breakablebarriers can be made of any number of materials known in the art thatcan hold fluid and break open upon suitable pressure withoutfragmenting, such as aluminum foil, rubber and/or plastic.

In another embodiment, as shown in FIG. 11, the plug 113 can beconfigured to have a hollow chamber for containing the hydration fluid.In this embodiment, the plug 113 may be designed in such a way as tohave a breakable bottom 130 so that fluid can be released to hydrate thebiosensor 118 when the user applies pressure to the plug. That is, invarious configurations, the plug 113 can rest atop the biosensor 118before use. When the user applies pressure to the plug 113, the floor130 of the plug 113 bursts open, releasing the fluid stored within theplug 113, bathing the biosensor 118 with hydrating fluid in the process.Accordingly, the breakable floor 130 can be made of any number ofmaterials known in the art that can hold fluid and break open uponsuitable pressure without fragmenting, such as aluminum foil, rubberand/or plastic. The plug 113 in accordance with this embodiment can beused in conjunction with the apparatus 100 in accordance with any of theembodiments discussed above.

Referring to FIG. 8, in another embodiment, the biosensor 118 can beloaded into the hydration storage compartment 110 located on theunderside of the apparatus 100 opposite the extension arm 108 a. Thiscan be accomplished, for example, with a plug 113 designed to cradle thebiosensor 118. In other words, for any and all embodiments, the plug canbe designed in a multitude of ways depending on the needs that arisefrom the configuration and location of the storage compartment 110 onthe apparatus 100. In this embodiment, it would be desirable to have theplug 113 shaped to cradle the biosensor 118 for easy loading of thebiosensor 118 from the underside of the apparatus 100, thereby loweringthe risk of having the biosensor 118 fall to the floor during biosensor118 loading. In an alternative embodiment for loading the biosensor intothe apparatus 100, the apparatus 100 can be flipped so that the storagecompartment 110 is on top and the user can load the biosensor 118 intothe compartment 110 and secure the biosensor 118 with the plug 113. Theuser can then flip the apparatus 100 back so that the storagecompartment 110 is on the bottom, and ready for the insertion process totake place.

In this arrangement, the plunger 108 would serve as a “lid” to thehydration storage compartment 110 as opposed to a “floor” as describedin other embodiments. Here, the plug 113 would serve as the “floor”,thereby trapping the biosensor 118 in the hydration storage compartment110. Similar to the other embodiments described above, once the distalend of the plunger 108 passes the hydration storage compartment 110 whenextension 108 a is located in proximity to the first ramp 112 c, thebiosensor 118 no longer has a restriction to entering into the channel106 and in front of the distal end of plunger 108. Once in thisposition, the apparatus 100 can be rotated sufficiently (i.e. flipped sothat the hydration storage compartment 110 is on top of the apparatus100) to allow the biosensor to fall into the circular channel 106 bygravity. The plug 113 could then be pushed toward the channel 106 tosecure the biosensor 118 into the channel 106.

Also referring to FIG. 8, the biosensor can be loaded into the apparatus100 from either end. In one embodiment, the biosensor 118 can be loadedinto the distal end of the hollow tube 102 when the extension 108 a isin proximity to the second ramp 112 b. The apparatus 100 can then beturned vertically so that once the biosensor 118 is inserted into thehollow tube 102 gravity causes the biosensor 118 to rest against thedistal end of plunger 108 when within the tube 106. The extension 108 acan then be moved backward to the first ramp 112 c, indicating to theuser that the biosensor is in proximity to the hydration storagecompartment 110. The user can then lower the apparatus 100 horizontallyso that the biosensor 118 can fall by gravity into the hydration storagecompartment 110 which resides in a position such that it is at thebottom of the apparatus 100 (as shown in FIG. 8). The extension 108 acan then be moved to the third ramp 112 a prior to insertion, securingthe biosensor 118 between the plunger 108 and plug 113. The biosensor118 can be hydrated in a substantially similar way as described aboveincluding pores or slot openings in the support device 104, plug 113 orchamber 110.

In accordance with another aspect of the present invention, referring toFIGS. 7 a-7 e, a package assembly is provided for storing the insertiondevice. FIG. 7 a illustrates a package assembly 700 according to oneembodiment in an unfolded and loaded configuration. In particular, thepackage assembly 700 includes a package assembly body 714 that has anapparatus cavity 709 configured to hold the apparatus 100 containing thebiosensor 118 in the hydration storage compartment 110. The cavity 709,in a preferred embodiment, is also configured to hold a sufficientvolume of fluid so that the fluid can enter the hydration storagecompartment 110 and bathe the biosensor 118, as illustrated in FIG. 7 a.Typically, the volume of fluid necessary to bathe the biosensor 118 willbe enough to fill the cavity surrounding the distal end of the hollowtube 102 and up to the location of the third ramp 112 a when the deviceis in the package 700 and the package 700 is standing in an uprightposition (as described below).

In one embodiment, the package assembly body 714 is shaped to secure theapparatus 100 so that the apparatus 100 remains substantially in placeeven if the package is otherwise moved. The apparatus 100 may be securedin the package assembly body 714 in any number of ways, including afriction fit mold. For example, as shown in FIG. 7 a, the packageassembly body 714 is fashioned to conform to the shape of the apparatus100, allowing the apparatus 100 to remain secure within the packageassembly 700. In one embodiment, engagement elements 713 frictionallyengage the apparatus to secure it in place. The package assembly 700 canbe made of any suitable material known in the packaging arts, such asplastic including, for example, thermoform plastic.

Referring to FIG. 7 b, the package assembly 700 containing the apparatus100 is sealed with a sterile barrier 704 to maintain the sterility ofthe apparatus and the biosensor 118. The sterile barrier 704 can be madeof any suitable material, such as, for example, woven plastic (such asTyvek®), paper or aluminum foil. In accordance with a preferredembodiment of the invention, the sterile barrier 704 is provided with aseptum 702 which allows the cavity 709 to be filled with hydrationand/or sterilization fluid while maintaining the sterility of thepackage and sterile barrier 704. In one embodiment, saline is injectedthrough the septum 702 with, for example, a syringe. This allows thebiosensor 118 to be hydrated while maintaining sterility within thepackage 700. The sterile barrier 704 is preferably attached to the face712 of the package body 714 in such a way so as to create a fluid-tightseal around the outer edge of the face 712 of the package body 714. Thiscan be accomplished with any number of glues or sealants known topersons skilled in the art.

Any number of hydration fluids can be used, such as, for example, one ormore of the following: (1) inorganic salts such as sodium chloride,potassium chloride, calcium chloride, or magnesium chloride; (2) buffersalts such as phosphate, HEPES, carbonate, and citrate; (3)preservatives such as EDTA; (4) antimicrobial agents such as sodiumazide, sulfites, and benzoates; (5) antibiotics, anti-inflammatory drugsand other pharmacological compounds; (6) ionic and nonionic surfactants;(7) thickening agents that can be used to increase the viscosity ofaqueous solutions such as glycerol, polyethylene glycols, gelatin, agarand pectin; (8) antioxidants such as BHT, BHA; (9) vitamins such as Cand E, flavonoids; and (10) Saccharides such as glucose, fructose, andsucrose. This list should not be construed to be exhaustive, but ismeant to illustrate the vast array of fluids that could be used tohydrate the biosensor.

In accordance with another aspect of the present invention, the package700 is designed to store the apparatus 100 in such a way so as to allowconstant hydration of the biosensor 118 while the biosensor 118 iscontained within the hydration storage compartment 110. In oneembodiment, as illustrated in FIG. 7 c, the package 700 standsvertically, allowing the sterile fluid to penetrate the hydrationchamber 110 and bathe the biosensor 118. Fluid may penetrate thehydration chamber 110 in any number of ways, including pores or slotopenings in the support device 104, plug 113 or chamber 110, asdescribed above.

In one embodiment, the package assembly 700 is configured in a verticalorientation by providing side walls 706 and 707 attached to the packageassembly body 714. Side walls 706 and 707 are shown in FIG. 7 a in aflat, unfolded configuration. Referring to FIGS. 7 b-d, the side walls706 and 707 are shown in a folded configuration. Referring to FIG. 7 d,in order to allow the sterile package 700 to remain standing inaccordance with one embodiment, package flaps 706 are folded away fromthe plane created by the face 712 of the package assembly 700 andsterile barrier 704. The flaps 706 are folded so as to connect with oneanother via slotted clasps 708, as illustrated in FIGS. 7 d and 7 e.This allows the package 700 to stand vertically thereby ensuring thatthe sterilization fluid collects in the cavity 709 so as to engulf thehydration storage compartment 110 of the apparatus 100 and thereby bathethe biosensor 118 prior to insertion into the subject.

While slotted clasps are illustrated as being formed from portions ofthe side walls 706 and 707, the side walls can be secured by othermeans. For example, the package assembly can be provided with one ormore back walls or clasps attached, for example, to one or both of sidewalls 706 and 707. In another embodiment, clasps are not formed from theside wall material but are, instead, attached to the side walls in anyknown manner, such as an adhesive.

Preferably, the apparatus 100, package 700, barrier 704, septum 702 andother relevant parts are manufactured of such materials that allow themto be readily disinfected and/or sterilize by conventional means.

While various embodiments/variations of the present invention have beendescribed above, it should be understood that they have been presentedby way of example only, and not limitation. Thus, the breadth and scopeof the present invention should not be limited by any of theabove-described exemplary embodiments, but should be defined only inaccordance with the following claims and their equivalents.

What is claimed is:
 1. An instrument for inserting a biosensor into asubject, said instrument comprising: a support device, wherein saidsupport device contains at least one channel; a plunger, wherein saidplunger is slidable within said channel; a compartment, said compartmenthaving a top end and a bottom end and wherein said compartment stores atleast one of said biosensors; a plug, wherein said plug is insertableinto the top end of the compartment; a hollow tube, wherein said hollowtube is attached to and extends from one end of said support device, andwherein said channel, plunger and hollow tube are configured such thatsaid biosensor can be expelled through said channel and hollow tube bysaid plunger and into said subject.
 2. The instrument of claim 1,wherein said compartment is a hydration compartment which is configuredto contain hydration fluid for hydrating said biosensor.
 3. Theinstrument of claim 2, wherein said hydration fluid is at least oneselected from the group consisting of: saline solution, inorganic salts,buffer salts, preservatives, antimicrobial agents, antibiotics,anti-inflammatory drugs, pharmacological compounds, ionic surfactants,nonionic surfactants, thickening agents, antioxidants, vitamins, andsaccharides.
 4. The instrument of claim 1, wherein said compartmentcontains a breakable floor.
 5. The instrument of claim 1, wherein saidplug includes a slot through which hydration fluid enters thecompartment.
 6. The instrument of claim 1, wherein said plug is made ofa porous material allowing fluid to enter said compartment.
 7. Theinstrument of claim 1, wherein said plug is made of solid material andcreates a fluid-tight friction fit within the walls of said compartment.8. The instrument of claim 1, wherein said plug contains a hollowchamber for containing hydrating fluid.
 9. The instrument of claim 8,wherein said plug contains a breakable bottom, wherein said breakablebottom breaks upon the application of pressure by the user and releasessaid hydrating fluid into the compartment.
 10. The instrument of claim1, wherein said support device is made of a porous material allowingfluid to enter said compartment.
 11. The instrument of claim 1, whereinsaid support device further comprises a first element that identifiesthe backward most position of the plunger within the channel.
 12. Theinstrument of claim 1, wherein said support device further comprises asecond element identified when the plunger and biosensor are positionedwithin the channel such that biosensor is positioned at the distal endof the hollow tube.
 13. The instrument of claim 1, wherein said supportdevice further comprises a third element that identifies the forwardmost position of the plunger within the channel.
 14. The instrument ofclaim 11, wherein said first element is a ramp that is configured toengage an extension arm extending from said plunger.
 15. The instrumentof claim 12, wherein said second element is a ramp that is configured toengage an extension arm extending from said plunger.
 16. The instrumentof claim 13, wherein said third element is a ramp that is configured toengage an extension arm extending from said plunger.
 17. The instrumentof claim 1, wherein said plunger contains at least one extension arm.18. The instrument of claim 1, wherein a hydration compartment can belocated opposite the extension arm.
 19. The instrument of claim 1,wherein said plug is substantially t-shaped and is configured toslidably engage the walls of said compartment.
 20. The instrument ofclaim 1, wherein said plug is shaped to cradle said biosensor.
 21. Theinstrument of claim 1, wherein said support device contains ridges toallow for ergonomic gripping of said instrument.
 22. The instrument ofclaim 1, wherein said support device contains at least one slot allowingan extension arm extending from said plunger to be moved back and forthalong said support device.
 23. The instrument of claim 1, wherein saidplunger is made of a guide wire.
 24. The instrument of claim 1, whereinsaid plunger is made of plastic.
 25. The instrument of claim 1, whereinsaid hollow tube is a needle.
 26. The instrument of claim 1, wherein thedistal end of said hollow tube is beveled.
 27. The instrument of claim1, wherein said plunger is a stylet.
 28. The instrument of claim 1,wherein said plunger has a beveled distal end matching a beveled end ofsaid tube.
 29. The instrument of claim 1, wherein said channel furthercomprises a first breakable barrier and second breakable barrier. 30.The instrument of claim 29, wherein said first and second breakablebarriers form part of the compartment for containing said biosensor andsaid hydration fluid.
 31. The instrument of claim 30, wherein thecompartment is sealed by a plug.
 32. The instrument of claim 30, whereinsaid plug is configured to secure said biosensor in said compartment.33. A method for inserting a biosensor into a subject comprising thesteps of: providing an instrument for inserting a biosensor into asubject comprising a support device containing at least one channel, aplunger slidable within said channel, a compartment that stores at leastone biosensor, a plug configured to secure said biosensor in saidcompartment, and a hollow tube which is attached to and extends from adistal end of said support device; moving said plunger to a firstposition of said support device to allow a biosensor to enter saidchannel of said support device; pushing said plug into said compartmentcontained in said support device to secure said biosensor within saidchannel of said support device; moving said plunger toward a secondposition of said support device to indicate to the user that saidbiosensor has traveled through said hollow tube and is about to entersaid subject; moving said plunger to a third position of said supportdevice to indicate to the user that said biosensor has exited saidhollow tube and entered said subject.
 34. The method of claim 33,wherein said biosensor is initially located within said compartment. 35.The method of claim 33, wherein said biosensor enters said channel bygravity.
 36. The method of claim 33, wherein ramps lock said plunger atsaid positions.
 37. A method for loading a biosensor into an insertiondevice comprising the steps of: providing an instrument for inserting abiosensor into a subject comprising a support device containing at leastone channel, a plunger slidable within said channel, a compartment thatstores at least one biosensor, a plug configured to secure saidbiosensor in said compartment, and a hollow tube which is attached toand extends from a distal end of said support device; moving saidplunger to a first position of said support device to allow room forsaid biosensor to be placed in the distal end of the hollow tube of saidsupport device; placing said biosensor inside said distal end of saidhollow tube; moving said plunger through said channel to a secondposition of said support device to allow said biosensor to travelthrough said channel and enter said compartment; moving said plunger toa third position of said support device to allow said biosensor to besecured between said plug and said plunger.
 38. The method of claim 37,wherein said biosensor rests against a distal end of said plunger whensaid plunger moves to said second position.
 39. The method of claim 37,wherein said biosensor enters said compartment by gravity.
 40. A packageassembly for storing a biosensor and apparatus for inserting a biosensorinto a subject comprising: a package body shaped to contain at least oneinsertion instrument within a cavity of said package body; a sterilebarrier sealed to said package body, wherein said sterile barriercontains at least one septum which allows said cavity to be filled withfluid, and wherein said barrier is sealed to said body so as to preventfluid from leaking from said cavity.
 41. The package assembly of claim40, wherein said package body is composed of plastic.
 42. The packageassembly of claim 40, wherein said sterile barrier is at least oneselected from the group consisting of: plastic, paper or aluminum foil.43. The package assembly of claim 40, wherein said septum prevents fluidfrom leaking out of said cavity.
 44. The package assembly of claim 40,wherein said package body is shaped to secure said instrument.
 45. Thepackage assembly of claim 40, wherein said instrument is secured to saidpackage body by friction fitting.
 46. The package assembly of claim 40,wherein said septum is configured to be pierced by a syringe.
 47. Thepackage assembly of claim 40, wherein said package assembly furthercomprises side walls extending form a front portion of said packagebody.
 48. The package assembly of claim 47, wherein said side wallsfurther comprise flap portions that can be engaged together.
 49. Thepackage assembly of claim 48, wherein said package assembly wherein saidside walls and flap portions enable the package assembly to standvertically.
 50. The package assembly of claim 48, wherein said flapportions further comprise slotted clasps.